The ABCs of Video Surveillance
|Copyright 2014 by Virgo Publishing.|
|By: Doug Carner|
|Posted on: 06/01/2003|
It's 2 a.m. Your storage site is closed and your manager is asleep. At one end of the property, an intruder has climbed your fence. Before he can reach the first unit, a siren sounds, floodlights illuminate, an armed response is on its way, and a video record of the entire event has just been e-mailed to your home. This is today's video surveillance.
Security that provides real and psychological value is a tangible asset that commands higher rental rates, reduced insurance premiums and increased control over your business. A professional surveillance system should:
Digital Video Recorders
The DVR was first introduced in the 1980s. Like a VCR, the DVR could originally only capture one video signal. If you had multiple cameras, you had to use a multiplexer to allow the images to share the same recording screen. This resulted in a significant loss in image detail. Alternatively, you could use a sequencer so each camera could take a turn being recorded. While this maintained image detail, each camera spent the majority of its time being unmonitored.
In the 1990s, DVRs and VCRs improved in terms of the amount of detail they could retain and how long they could record. By the end of the millennium, DVR recording quality had clearly surpassed that of the VCR. DVRs could simultaneously monitor dozens of cameras without losing any image detail. Imbedded intelligence allowed the DVR to make judgment calls as to what was worthy of recording and what response should be taken.
Today, DVRs take full advantage of the Internet and allow multiple remote-viewing capabilities. In self-storage, this means you gain remote control over your business in addition to a marketing tool to lure prospects. Tenants will gladly pay a premium after knowing your security will catch intruders before their RVs or boats can be harmed or stolen.
A commercial-grade DVR should offer all of the features noted above. It should also record at a resolution (measured in pixels) that is at least as good as that of your cameras. Never accept DVRs that record at only 76,800 pixels (a 320x240 resolution). Doing so will render your recording resolution inferior to that of the cheapest VCR. A quality DVR will provide 640x480-resolution recording, representing more than a quarter-million pixels of detail per camera.
To capture smooth motion, the DVR should record at 120 frames per second (this speed is divided among all active cameras). Once the DVR's hard drive is full, it will automatically overwrite the oldest images. To ensure you can recall the last week or two of activity, your DVR should have at least 100 gigabytes of storage.
DVRs come preconfigured for four, eight or 16 cameras. The DVR you choose should include a CD writer to permanently store images that might be needed by the police or insurance company. If the DVR includes a sound card, your office video records will include a soundtrack.
Camera technology has also made quantum leaps in form and function. Gone are the days of mailbox-sized camera housings, as they have become a popular theft item. Modern surveillance cameras are compact enough to hide inside alarm-bell boxes, access keypads and weatherproof housings the size of your thumb. Yet their diminutive size is misleading, as their image quality exceeds that of their larger predecessors.
When it comes to surveillance cameras, image quality depends on what's inside. The viewed image enters through the camera lens and iris. The job of the iris is to regulate the amount of light that enters the body of the camera. Too much light saturation, and the images are featureless white blobs. Too little light, and the objects appear as dark shadows. If the camera is in a controlled lighting environment, like an interior hallway, a manual iris can be used. Otherwise, an auto-iris will be required to optimize the view.
Camera lenses are rated in millimeters (mm). A 3.6mm lens provides a view similar to the naked eye. These are the lenses of choice for small areas like office spaces and elevator lobbies. An 8mm is a general-purpose lens well-suited to most outdoor spaces. It provides a view that is similar to looking through the cardboard center of a toilet paper roll. For an even more telescopic view, choose a 12mm lens, which is the best choice for monitoring long rows of units. You can purchase variable zoom lenses that span the full range of choices. However, if you determine the correct lens prior to installation, there is no need to pay extra to add a variable lens.
The camera lens passes its view to the camera's imager. The recommended resolution is 525 lines. Anything less may make it impossible to read a license plate or recognize a face. To save money, several vendors still provide cameras with 440 or less resolution. Not all imagers are created equal, and there are dramatic differences in picture quality among brands.
Surveillance cameras are available with either analog or digital circuitry. Digital cameras are more compact, draw less power, and eliminate the need for an iris by automatically compensating for changes in lighting. Almost all digital cameras contain electronics made by Sony or Sanyo. The highest-grade cameras will incorporate the "full Sony chipset." Previously available to only the wealthiest clients, digital cameras have been steadily dropping in price.
Color surveillance cameras have become so light-sensitive they provide the low-light capability previously available only with black-and-white models. However, if you need a camera that can see in near or complete darkness, select a black/white model with a built-in infrared illuminator. Thieves can't see the camera, even though the camera can clearly see them. There are even models that operate in color during the day and automatically switch to black and white at night.
Each camera requires a mount and, if exposed to the elements, a protective housing. If the camera temperature might drop below freezing, the housing also requires a heater or expensive freeze-proof circuitry. Alternatively, the camera housing and mount can be combined into a dark dome that disguises the camera's direction of view. Lastly, you need a power supply to operate the camera and its components.
To recap, each camera is made of many parts: camera body, lens, iris, housing, mount and power supply. These items are sold separately, which makes the camera seem inexpensive until you add the costs together. Your vendor should be able to combine all of these items into a package that costs less than $600 per camera for a top-of- the-line model.
Putting it All Together
Common RG-59 coax cable brings the signal from the camera back to the DVR. In almost every county, you can "free run" this cable, which is a great cost savings considering you might have runs up to 2,000 feet when you cannot take a direct path.
If your pavement is already laid, or you need to cover nonadjacent property, consider going wireless. For about $100 more than a regular camera, you can get a short-range 2.4-GHz wireless camera. You are limited to only four channels, and one may already have area interference from a neighbor's cordless phone. Thus, you should not plan on having more than three wireless cameras per site.
You can add several more cameras using expensive 5.4-GHz cameras. These will become more affordable in the coming years. By contrast, 900-MHz cameras have been discontinued due to the popularity of cordless phones. The resulting oversaturation has rendered the 900 MHz band far too unstable for use with security equipment.
There are also wire-free cameras that transmit their video signal over your pre-existing AC power lines. Wire-free cameras can be placed anywhere at your site without running an inch of wiring. They can be easily relocated during the construction phase and make the perfect camera for discreet observations.
Cameras should be mounted at a height of at least 10 feet to keep them out of the reach of vandals. If you have a light pole at your site, consider mounting several cameras aimed in different directions. I do not recommend using a platform that pans the camera back and forth. Panning will cause your DVR to record constantly, and critical events may occur while the camera is aiming elsewhere. It is better to place additional cameras to provide complete security coverage.
A skilled security vendor can lay out a camera placement that will cover your storage units, office, dumpster, elevator, stairwell, access doors, drive-up gates, manager's apartment, perimeter fencing and other sensitive areas. A high-end 16-camera system should cost approximately $15,000 and include the DVR, cameras, monitor, Internet connectivity and everything else needed except coax cable. Contact several vendors and compare features and costs. You will find features, price and skill level vary dramatically.
Doug Carner is on the Western-region board of directors for the Self Storage Association. He is also the vice president of QuikStor Security & Software, a California-based company specializing in access control, management software, digital video surveillance and corporate products for the self-storage industry. For more information, call 800.321.1987; e-mail firstname.lastname@example.org; visit www.quikstor.com.